The invention relates generally to systems and methods for loading transmission sources used in imaging systems.
Imaging systems play an important role in the practice of medicine and the administration of health care to patients. Imaging systems allow physicians to diagnose otherwise undetectable problems throughout the body. For example, Positron Emission Tomography (“PET”) imaging systems allow a physician to examine the heart, brain, and other organs, by producing images that show the chemical functioning of an organ or tissue. Most PET imagers operate by placing a patient on a cradle and moving the cradle into the gantry's patient bore, where the scanning takes place. The patient bore is lined by a series of detector rings that gather imaging data when the imager is scanning. The detector rings utilize crystals to measure coincidence events when radiation is released into the scanning area. The necessary radiation is released when a transmission source, or radioactive source, is rotated by a transmission ring around the inside perimeter of the detector rings. The data gathered by the crystals is used to produce the medical image of the patient's body.
The transmission source is often constructed of radioactive material, which can be harmful to humans after prolonged exposure. Accordingly, the transmission source for an imaging system must be kept within a shielded container until the imaging system is ready for use. Transferring the transmission source from the shielded container to a location where it can be rotated around the detector rings has presented several problems.
For example, some conventional PET imaging systems utilize a robotic arm to transfer the transmission source from the shielded storage container to the transmission ring. One disadvantage of the robotic arm is that it requires several mechanical movements including both rotation and translation. More specifically, the robotic arm must extend into the storage container to take hold of the transmission source, and pull out of the storage container without dropping the transmission source or letting it come into contact with any other structures. Outside the storage container, the robotic arm must once again move into position with the transmission ring. Each of these difficult movements is controlled by complex logic sequences governing the movements of the armature and transmission source. In addition, the reliability of this robotic armature is highly dependant on several geometric and dimensional tolerances based on the length of the robotic armature, and the cantilevered mount attached to the translation gearbox. The accuracy and reliability of the robotic armature is extremely important given that the transmission source must be precisely positioned within the transmission ring while in use, and in the storage container when not in use.
An additional disadvantage is that these robotic arms utilize a mechanical claw-like means, which must hold and at appropriate times release the transmission source. This design occasionally results in the transmission source being dropped during transfer.
For at least these reasons, there is a need for the continuous support of transmission sources at all times during loading and unloading. There is also the need for simplifying the rotational and translational paths the transmission source must take when moving from storage to loading positions. There is also a need for simplifying and improving the mechanical means used to grip and hold the transmission source during loading and unloading. Overcoming these disadvantages will lower the risk of the transmission source being dropped, which in turn will reduce imaging system downtime.
The invention provides apparatuses, systems and methods for source loading in imaging systems, that overcome the disadvantages of known systems and methods while offering features not present in known systems and methods.